scholarly journals Effect of Acoustic Resonance Condition on Wake Generated Rotor Blade Gust Response

1993 ◽  
Author(s):  
Steven R. Manwaring ◽  
Sanford Fleeter
Keyword(s):  
Rotor Blade ◽  
Resonance Condition ◽  
Axial Flow ◽  
Acoustic Resonance ◽  
Pressure Response ◽  
Rotor Blades ◽  
Flow Models ◽  
Unsteady Pressure ◽  
Unsteady Aerodynamic ◽  
Blade Row

Unsteady aerodynamic blade row response is generally categorized as either subresonant or superresonant, with an acoustic resonance at the points where these regions meet. Although these far field acoustic responses are critical to obtaining correct predictions from linearized unsteady flow models, they are a subject of some controversy, both analytically and experimentally. In this paper, multistage axial flow compressor acoustic resonance conditions, including both subresonant and superresonant unsteady aerodynamic response in the immediate vicinity of an acoustic resonance, are experimentally investigated. This is accomplished by quantifying these acoustic resonance and subresonant and superresonant blade row interaction phenomena in terms of their effect on the rotor blade row periodic unsteady pressure response. The subresonant and superresonant acoustic environments are established by changing the number of vanes while maintaining the number of rotor blades, thereby altering the unsteady stator-rotor interactions and the interblade phase angle and by varying the Mach number without changing the blade row interactions. First the first stage rotor row periodic unsteady pressure response to a downstream stator-rotor interaction generated acoustic wave is studied. Then, the gust unsteady aerodynamic response of the first stage rotor row due to IGV wakes, with the IGV-instrumented first stage rotor itself configured to generate subresonant and superresonant conditions is considered. Appropriate data are correlated with predictions.

Rotor Blade Unsteady Aerodynamic Gust Response to Inlet Guide Vane Wakes

1993 ◽  
Vol 115 (1) ◽  
pp. 197-206 ◽  
Author(s):  
S. R. Manwaring ◽  
S. Fleeter
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Axial Flow ◽  
Unsteady Aerodynamics ◽  
Rotor Blades ◽  
Inlet Guide Vane ◽  
Unsteady Aerodynamic ◽  
Forcing Function ◽  
Reduced Frequency ◽  
Flow Compressor

A series of experiments is performed in an extensively instrumented axial flow research compressor to investigate the fundamental flow physics of wake-generated periodic rotor blade row unsteady aerodynamics at realistic values of the reduced frequency. Unique unsteady data are obtained that describe the fundamental unsteady aerodynamic gust interaction phenomena on the first-stage rotor blades of a research axial flow compressor generated by the wakes from the inlet guide vanes. In these experiments, the effects of steady blade aerodynamic loading and the aerodynamic forcing function, including both the transverse and chordwise gust components, and the amplitude of the gusts, are investigated and quantified.

Rotor Blade Unsteady Aerodynamic Gust Response to Inlet Guide Vane Wakes

1991 ◽  
Author(s):  
Steven R. Manwaring ◽  
Sanford Fleeter
Keyword(s):  
Rotor Blade ◽  
Guide Vane ◽  
Axial Flow ◽  
Unsteady Aerodynamics ◽  
Rotor Blades ◽  
Inlet Guide Vane ◽  
Unsteady Aerodynamic ◽  
Forcing Function ◽  
Reduced Frequency ◽  
Flow Compressor

A series of experiments are performed in an extensively instrumented axial flow research compressor to investigate the fundamental flow physics of wake generated periodic rotor blade row unsteady aerodynamics at realistic values of the reduced frequency. Unique unsteady data are obtained which describe the fundamental unsteady aerodynamic gust interaction phenomena on the first stage rotor blades of a research axial flow compressor generated by the wakes from the Inlet Guide Vanes. In these experiments, the effects of steady blade aerodynamic loading and the aerodynamic forcing function, including both the transverse and chordwise gust components, and the amplitude of the gusts, are investigated and quantified.

scholarly journals Aerodynamic Detuning Analysis of an Unstalled Supersonic Turbofan Cascade

1986 ◽  
Vol 108 (1) ◽  
pp. 60-67 ◽  
Author(s):  
D. Hoyniak ◽  
S. Fleeter
Keyword(s):  
Flow Field ◽  
Leading Edge ◽  
Rotor Blades ◽  
Driving Mechanism ◽  
Aeroelastic Stability ◽  
Aerodynamic Forces ◽  
Unsteady Aerodynamic ◽  
Influence Coefficients ◽  
Blade Row ◽  
The Stability

A new, and as yet unexplored, approach to passive flutter control is aerodynamic detuning, defined as designed passage-to-passage differences in the unsteady aerodynamic flow field of a rotor blade row. Thus, aerodynamic detuning directly affects the fundamental driving mechanism for flutter, i.e., the unsteady aerodynamic forces and moments acting on individual rotor blades. In this paper, a model to demonstrate the enhanced supersonic unstalled aeroelastic stability associated with aerodynamic detuning is developed. The stability of an aerodynamically detuned cascade operating in a supersonic inlet flow field with a subsonic leading edge locus is analyzed, with the aerodynamic detuning accomplished by means of nonuniform circumferential spacing of adjacent rotor blades. The unsteady aerodynamic forces and moments on the blading are defined in terms of influence coefficients in a manner that permits the stability of both a conventional uniformly spaced rotor configuration as well as the detuned nonuniform circumferentially spaced rotor to be determined. With Verdon’s uniformly spaced Cascade B as a baseline, this analysis is then utilized to demonstrate the potential enhanced aeroelastic stability associated with this particular type of aerodynamic detuning.

Influence of Rain Ingestion on the Endwall Treatment in an Axial Flow Compressor

2018 ◽  
Vol 140 (8) ◽  
Author(s):  
Jichao Li ◽  
Juan Du ◽  
Mingzhen Li ◽  
Feng Lin ◽  
Hongwu Zhang ◽  
...  
Keyword(s):  
Rotor Blade ◽  
Axial Flow ◽  
Pressure Rise ◽  
Water Film ◽  
Stall Margin ◽  
Axial Flow Compressor ◽  
Water Ingestion ◽  
Blade Row ◽  
Flow Compressor ◽  
The Stability

The effects of water ingestion on the performance of an axial flow compressor are experimentally studied with and without endwall treatment. The background to the work is derived from the assessment of airworthiness for an aero-engine. The stability-enhancing effects with endwall treatments under rain ingestion are not previously known. Moreover, all the endwall treatments are designed under dry air conditions in the compressor. Water ingestion at 3% and 5% relative to the design mass flow proposed in the airworthiness standard are applied to initially investigate the effects on the performance under smooth casing (SC). Results show that the water ingestions are mainly located near the casing wall after they move through the rotor blade row. The pressure rise coefficient increases, efficiency declines, and torque increases under the proposed water ingestion. The increase of the inlet water increases the thickness of the water film downstream the rotor blade row and aggravates the adverse effects on the performances. Subsequently, three endwall treatments, namely circumferential grooves, axial slots, and hybrid slots–grooves, are tested with and without water ingestion. Compared with no water ingestion, the circumferential grooves basically have no resistance to the water ingestion. The axial slots best prevent the drop of the pressure rise coefficient induced by water ingestion, and hybrid slots–grooves are the second-best place owing to the contribution of the front axial slots. Therefore, the hybrid slots–grooves can not only extend the stall margin with less efficiency penalty compared with axial slots, but also prevent rain ingestion from worsening the compressor performance.

Presentation of a Blade-Design Method for Axial-Flow Turbines, Including Design and Test Results of a Typical Axial-Flow Stage

1960 ◽  
Vol 82 (1) ◽  
pp. 19-26
Author(s):  
F. Baumgartner ◽  
R. Amsler
Keyword(s):  
Design Method ◽  
Axial Flow ◽  
Rate Of Change ◽  
Rotor Blades ◽  
Test Results ◽  
Blade Loading ◽  
Blade Row ◽  
Consistent Manner ◽  
The Mean ◽  
Typical Design

A method is presented to determine the shape of stationary nozzle blades and rotor blades for an axial-flow-type turbine in a generally consistent manner based on the concept of aerodynamic blade loading. The mean blade load is a typical design parameter which predominantly determines the blade curvature. It depends in particular on the rate of change of momentum across the blade row. By applying the design method, airfoil shapes are obtained which satisfy the momentum requirements regardless of what blade-load distribution is assumed as long as the mean blade load remains constant. A specific application of the design method is described and test data are presented which show that good agreement between design goal and test results was achieved.

scholarly journals Effect of Rotor Tip Clearance and Configuration on Overall Performance of a 12.77-Centimeter Tip Diameter Axial-Flow Turbine

1979 ◽  
Author(s):  
J. E. Haas ◽  
M. G. Kofskey
Keyword(s):  
Experimental Investigation ◽  
Rotor Blade ◽  
Axial Flow ◽  
Single Stage ◽  
Rotor Blades ◽  
Tip Clearance ◽  
Blade Height ◽  
Overall Performance ◽  
Flow Reaction ◽  
The One

An extensive experimental investigation was made to determine the effect of varying the rotor tip clearance of a 12.77-cm-tip diameter, single-stage, axial-flow reaction turbine. In this investigation, the rotor tip clearance was obtained by use of a recess in the casing above the rotor blades and also by use of a reduced blade height. For the recessed casing configuration, the optimum rotor blade height was found to be the one where the rotor tip diameter was equal to the stator tip diameter. The tip clearance loss associated with this optimum recessed casing configuration was less than that for the reduced blade height configuration.

Vortex Transport and Blade Interactions in High Pressure Turbines

2003 ◽  
Author(s):  
V. S. P. Chaluvadi ◽  
A. I. Kalfas ◽  
H. P. Hodson
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Rotor Blade ◽  
Delta Wing ◽  
Classical Model ◽  
Three Dimensional ◽  
Axial Flow ◽  
Passage Vortex ◽  
Blade Row ◽  
The Impact

This paper presents a study of the three-dimensional flow field within the blade rows of a high-pressure axial flow steam turbine stage. Half-delta wings were fixed to a rotating hub to simulate an upstream rotor passage vortex. The flow field is investigated in a Low-Speed Research Turbine using pneumatic and hot-wire probes downstream of the blade row. The paper examines the impact of the delta wing vortex transport on the performance of the downstream blade row. Steady and unsteady numerical simulations were performed using structured 3D Navier-Stokes solver to further understand the flow field. The loss measurements at the exit of the stator blade showed an increase in stagnation pressure loss due to the delta wing vortex transport. The increase in loss was 21% of the datum stator loss, demonstrating the importance of this vortex interaction. The transport of the stator viscous flow through the rotor blade row is also described. The rotor exit flow was affected by the interaction between the enhanced stator passage vortex and the rotor blade row. Flow underturning near the hub and overturning towards the mid-span was observed, contrary to the classical model of overturning near the hub and underturning towards the mid-span. The unsteady numerical simulation results were further analysed to identify the entropy producing regions in the unsteady flow field.

Unsteady Aerodynamic Interactions in a Multistage Compressor

1987 ◽  
Vol 109 (3) ◽  
pp. 420-428 ◽  
Author(s):  
V. R. Capece ◽  
S. Fleeter
Keyword(s):  
Axial Flow ◽  
Unsteady Aerodynamic ◽  
Geometric Conditions ◽  
Forcing Function ◽  
Reduced Frequency ◽  
Aerodynamic Interaction ◽  
Blade Row ◽  
Unsteady Interaction ◽  
Multistage Compressor ◽  
Series Of Experiments

The fundamental flow physics of multistage blade row interactions is experimentally investigated, with unique data obtained which quantify the unsteady harmonic aerodynamic interaction phenomena. In particular, a series of experiments is performed in a three-stage axial flow research compressor over a range of operating and geometric conditions at high reduced frequency values. The multistage unsteady interaction effects of the following on each of the three vane rows are investigated: (1) the steady vane aerodynamic loading, (2) the waveform of the aerodynamic forcing function to each vane row, including both the chordwise and traverse gust components.

Numerical Simulation and Flow Field Measurement of High Efficiency Axial-Flow Pump

2009 ◽  
Author(s):  
De-sheng Zhang ◽  
Wei-dong Shi ◽  
Bin Chen ◽  
Xing-fan Guan
Keyword(s):  
Rotor Blade ◽  
Radial Direction ◽  
High Efficiency ◽  
Static Pressure ◽  
Axial Flow ◽  
Rotor Blades ◽  
Experimental Results ◽  
Meridional Velocity ◽  
Axial Flow Pump ◽  
Flow Pump

In order to analyze the flow characteristics of a high efficiency axial-flow pump, the behavior of the flow in an adjustable axial-flow pump bas been analyzed by numerical simulations of the entire stage based on Fluent software. The prediction data shows agreement with the experimental results. Numerical results show that the static pressure on pressure side of rotor blades increases slightly at radial direction, and remains almost constant in circumferential direction at design conditions, while it increases gradually from inlet to exit on suction side along the flow direction. The static pressure, total pressure and velocity at inlet, rotor blade exit and stator outlet were measured by five-hole probe. The experimental results show, inlet flow is almost axial and the prerotation is very small at design conditions. The meridional velocity and circulation distributions are almost uniform at rotor blades exit at design condition. The residual circulation still exists at downstream of stator, and the absolute flow angle at radial direction is almost consistent at design conditions, but Cu increases linearly from hub to tip at small flow rate conditions. To determine the influence of the hub leakage, a contrast experiment was accomplished. The measurement results show that hub leakage results in the decrease of efficiency, and the meridional velocity and circulation at rotor blade exit, especially near hub leakage region are influenced by the leakage.

Experimental Investigation of Multistage Interaction Gust Aerodynamics

1989 ◽  
Vol 111 (4) ◽  
pp. 409-417 ◽  
Author(s):  
V. R. Capece ◽  
S. Fleeter
Keyword(s):  
Axial Flow ◽  
Unsteady Aerodynamics ◽  
Unique Data ◽  
Aerodynamic Loading ◽  
Unsteady Aerodynamic ◽  
Forcing Function ◽  
Reduced Frequency ◽  
Aerodynamic Interaction ◽  
Blade Row ◽  
Potential Interactions

The fundamental flow physics of multistage blade row interactions are experimentally investigated at realistic reduced frequency values. Unique data are obtained that describe the fundamental unsteady aerodynamic interaction phenomena on the stator vanes of a three-stage axial flow research compressor. In these experiments, the effect on vane row unsteady aerodynamics of the following are investigated and quantified: (1) steady vane aerodynamic loading; (2) aerodynamic forcing function waveform, including both the chordwise and transverse gust components; (3) solidity; (4) potential interactions; and (5) isolated airfoil steady flow separation.

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